[Federal Register: December 18, 2003 (Volume 68, Number 243)]
[Page 70523-70526]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

Endangered and Threatened Wildlife and Plants; 90-Day Finding for
a Petition to Delist the Preble's Meadow Jumping Mouse in Colorado and

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.


SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 90-
day finding for a petition to delist the Preble's meadow jumping mouse
(Zapus hudsonius preblei) under the Endangered Species Act of 1973, as
amended. We find that the petition and additional information in our
files did not present substantial scientific or commercial information
indicating that delisting may be warranted. We will not be initiating a
further status review in response to this petition. We ask the public
to submit to us any new information that becomes available concerning
the status of or threats to this species. This information will help us
monitor and encourage the conservation of this species.

DATES: The finding announced in this document was made on December 11,
2003. You may submit new information concerning this species for our
consideration at any time.

ADDRESSES: Questions or information concerning this petition should be
sent to the Field Supervisor, U.S. Fish and Wildlife Service,
Ecological Services, 755 Parfet, Lakewood, Colorado 80215. The separate
petition finding, supporting data, and comments are available for
public review, by appointment, during normal business hours at the
above address.

FOR FURTHER INFORMATION CONTACT: Ms. Susan Linner at 303-275-2370 (see
ADDRESSES section).



    Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as
amended (16 U.S.C. 1531 et seq.), requires that the Service make a
finding on whether a petition to list, delist, or reclassify a species
presents substantial scientific or commercial information to
demonstrate that the petitioned action may be warranted. This finding
is to be based on all information readily available to the Service at
the time the finding is made. To the maximum extent practicable, the
finding shall be made within 90 days following receipt of the petition
and promptly published in the Federal Register. Following a positive
finding, section 4(b)(3)(B) of the Act requires the Service to promptly
commence a status review of the species.
    The Preble's meadow jumping mouse is a small rodent in the family
Zapodidae and is 1 of 12 recognized subspecies of the species Zapus
hudsonius, the meadow jumping mouse. Preble's is native only to the
Rocky Mountains-Great Plains interface of eastern Colorado and
southeastern Wyoming. This shy, largely nocturnal mouse is 8 to 9
inches long (its tail accounts for 60 percent of its length) with hind
feet adapted for jumping. It occurs in foothills riparian habitat from
southeastern Wyoming to south central Colorado. Preble's meadow jumping
mice regularly use upland grasslands adjacent to riparian habitat, and
they may be dependent upon some amount of open water. The species
hibernates near riparian zones from mid-October to early May. Loss of
riparian habitats and other factors associated with urbanization appear
to be the major threat to the species.
    On August 16, 1994, the Service received a petition from the
Biodiversity Legal Foundation to list the Preble's

[[Page 70524]]

meadow jumping mouse. On March 15, 1995, the Service published a notice
of the 90-day finding that the petition presented substantial
information indicating that listing the Preble's may be warranted, and
requested comments and biological data on the status of the mouse (60
FR 13950). On March 25, 1997, the Service issued a 12-month finding on
the petition action along with a proposed rule to list Preble's as an
endangered species and announced a 90-day public comment period (62 FR
14093), with subsequent reopenings of the comment period to gather
additional information (62 FR 24387, 62 FR 67041). The Service added
the Preble's meadow jumping mouse to the List of Endangered and
Threatened Wildlife in 50 CFR 17.11 as a threatened species on May 13,
1998 (63 FR 26517).
    On July 27, 1999, the Service received a petition to delist the
Preble's, dated July 20, 1999. The Service subsequently received two
other petitions to delist the Preble's--one dated July 26, 1999, and
one dated August 27, 2000. These petitions are being treated as second
petitions for the requested delisting action, and both have been
considered in this 90-day finding.

Review of the Petition

    In requesting that the Service delist the Preble's, the first
petitioner stated that the information available to the Service did not
justify a listing and asked the Service to ``set aside'' the Act
relative to the Preble's to allow time to gather more information. The
third petitioner stated that, because the information available on the
Preble's is limited, the Service's listing of the subspecies was
``precipitate and uninformed.'' The Service is mandated to use the best
scientific information available at the time we make a decision to list
a species (50 CFR 424.11(b)). Once petitioned to list a species, we are
under statutory obligations as stated in the Act to complete the
petition process. We did extend or reopen the comment period twice and
held three public hearings to seek factual reports or information that
might contribute to the development of the final rule (63 FR 26517).
    The first petitioner stated that additional information was
available on trapping conducted by private landowners, the Forest
Service, and the State Department of Transportation that the Service
did not consider in its 1998 listing and that the Service should set
aside the listing to evaluate this new information. The third
petitioner stated that the information coming to light in 1999
indicated a plenitude of this subspecies. Trapping conducted by private
landowners, the Forest Service, and the Wyoming Department of
Transportation in a number of potential habitat sites in the North
Platte drainage occurred after the species was listed as threatened in
1998. Although the Service did not have this trapping information
available for consideration during preparation of the 1998 listing
rule, we did consider in the listing rule that the Preble's likely
occurred in these areas because the species historically had been
collected there and these areas have suitable habitat for the Preble's.
Therefore, the Service took into consideration the likely presence of
the Preble's in these surveyed locations in the 1998 listing rule.
    The second petitioner stated that the reason for the delisting
request was the inability to identify the mouse. We interpret this
concern, that is the difficulty in differentiating Preble's from the
western jumping mouse in the field, as either a concern that (1) the
listing is invalid or (2) the taxonomic entity is not valid. The range
of the western jumping mouse (Zapus princeps) in Wyoming and Colorado
overlaps that of Preble's (Hall 1981), and the two species are similar
in their appearance. Despite difficulties in field identification, the
Preble's can be differentiated from the western jumping mouse. Compared
to the western jumping mouse, the Preble's is generally smaller and has
a more distinctly bicolored tail and a less obvious dorsal (back)
stripe. A better technique for identification of the Preble's requires
skulls of specimens housed in natural history museums, where dental
characteristics (such as the presence or absence of a tooth fold on the
first lower molar (Klingener 1963, Hafner 1993) or the shape of a tooth
cusp) can be seen and used in combination with distribution and
elevation. These techniques have been useful scientific tools for
almost half a century. A third and more recent technique to identify
Preble's uses a combination of skull measurements in addition to the
tooth fold (which may not always be reliable by itself due to tooth
wear) (Conner and Shenk in press). These techniques accurately identify
most of the Preble's specimens. A fourth technique is genetic analysis.
Future DNA studies, including a current study being conducted at the
Denver Museum of Nature and Science, will go a long way towards
resolving some of the few remaining identification inconsistencies.
    In addition, ease of field identification is not a threat to be
evaluated when making a listing determination. The Act requires that
the Service evaluate five factors in determining whether to list a
taxon as endangered or threatened. Under section 4(a)(1) of the Act, we
must determine whether a species should be listed as threatened or
endangered due to one or more of the following five factors--(1)
present or threatened destruction, modification, or curtailment of
habitat or range; (2) overutilization for commercial, recreational,
scientific, or educational purposes; (3) disease or predation; (4) the
inadequacy of existing regulatory mechanisms; and (5) other natural or
manmade factors affecting the species' continued existence. Our
determination is statutorily limited to an evaluation of these five
    In response to whether the taxonomic entity is valid, the Code of
Federal Regulations (50 CFR 424.11) states that in listing entities as
endangered or threatened under the Act, the Service will rely on
standard scientifically accepted taxonomy. The Preble's meadow jumping
mouse (Zapus hudsonius preblei) is a valid, scientifically accepted
subspecies of meadow jumping mice (Zapus hudsonius) (Krutzch 1954;
Clark and Stromberg 1987; Fitzgerald et al. 1994).
    The third petitioner disagreed with the use of information
available on Zapus hudsonius and the application of this information to
Zapus hudsonius preblei. When information specific to a subspecies is
lacking, information on the parent species may be the best information
available for the Service to use. We must base our determination on the
best available scientific information. Many characteristics of the
species Z. hudonius would generally be applicable to all its
subspecies, including Z. h. preblei.
    The third petitioner stated that the original petition to list the
Preble's should not have been given credence because it lacked
sufficient information on the Preble's. Under the Code of Federal
Regulations (50 CFR 424.13 and 424.14), the Service is required to
seriously consider all petitions and utilize all available information,
not just the petitioner's, when making its determination. In the 1998
listing rule, we relied on a host of scientific information available
on the species concerning the threats it faced and did not make our
determination based solely on the information provided in the original
    The third petitioner stated that the 1998 listing is inappropriate
because of errors in the subspecies' geographical distribution. The
third petitioner stated that the Service did not accept the
identification of an individual Preble's reportedly found in Las Animas
County, Colorado, because it would have raised

[[Page 70525]]

questions regarding the subspecies' presence in Huerfano, Costilla, and
Pueblo Counties of Colorado. As stated in the 1998 listing rule, the
Service did not accept this identification because further
morphological analysis determined this individual to be a different
species of mouse, the western jumping mouse, not the Preble's.
    The third petitioner stated that favorable habitat may occur in
other Colorado counties (Gilpin, Clear Creek, Fremont, Teller,
Huerfano, and Costilla) that have not been surveyed. Since receipt of
the third petitioner's petition, surveys have been undertaken in
Fremont and Teller Counties. Gilpin, Clear Creek, and Teller are high-
elevation counties west of known Preble's distribution with almost no
favorable habitat. The only favorable habitat would occur where these
counties meet lower elevation neighboring counties. The lower elevation
habitat within the South Platte River drainage in northern Teller
County may be occupied by the Preble's near the Jefferson County line.
Surveys identified one Preble's mouse at approximately the county line
but none upstream within Teller County. The habitat in Teller County is
very limited in extent because the elevation rapidly becomes too high
upstream from Teller County's border with Jefferson County. Similarly,
elevations in Gilpin and Clear Creek Counties are generally too high to
support the Preble's. At the eastern edge of both counties, mountain
drainages exit into Jefferson County to lower elevation streams
characteristic of the subspecies' range. Surveys of lower elevation
streams in Gilpin and Clear Creek Counties suggest that habitat is
marginal, at best, for the Preble's. Any additional habitat in these
counties would not significantly increase the size of the Preble's
geographical distribution and, therefore, would not alter the threat
analysis in the 1998 listing rule.
    Fremont, Costilla, and Huerfano Counties are not likely to support
Preble's. Surveys of possibly suitable habitats in Fremont County have
failed to document the Preble's (Christina Werner, Colorado Natural
Heritage Program, in litt. 2003). While a portion of Huerfano County is
within the Arkansas River drainage (where Preble's has been documented
in the northernmost part), Huerfano County is even further south of
known Preble's range and is even less likely to have suitable habitat
for the Preble's. Costilla County is in the Rio Grande drainage. It
lies far from known Preble's range, south and west of the Arkansas
River drainage and separated by a mountain range.
    The third petitioner stated the use of Sherman live traps as a
reason why the subspecies' geographical distribution cannot be fixed
entirely. The geographical distribution of the subspecies was
determined based on small mammal surveys conducted in Colorado and
Wyoming over the past 100 years primarily using snaptraps, not Sherman
live traps. Therefore, surveys using Sherman live traps were not the
primary information used to determine the species' geographical
distribution. The use of Sherman live traps in surveying for Preble's
became standard methodology in the early 1990s, and information from
these surveys has refined but not significantly altered the subspecies
geographical distribution.
    Additionally, the third petitioner stated that the Service did not
accurately identify the Preble's geographical range because of what the
petitioner stated were errors in several citations (Whitaker 1972;
Compton and Hugie 1993; Harrington et. al. 1995, and Meaney and
Clippenger 1996). In defining the geographical distribution, the
Service used all scientific information available; it did not rely only
upon the citations mentioned by the third petitioner but used other
citations as well to give a full picture of the species' range.
    The third petitioner cites Shenk (1998) as saying that there is
insufficient information on Preble's range and ecology. While Shenk
cites gaps in knowledge on the Preble's, Shenk's intent was to identify
information needed to support a conservation strategy for the Preble's
and was not related to the species' listing.
    The third petitioner stated that population declines have not been
documented. The Preble's has been extirpated from some historically
occupied areas. Surveys have identified various locations where the
subspecies was historically present but is now absent (Ryon 1996).
Since at least 1991, the Preble's has not been found in Denver, Adams,
or Arapahoe Counties in Colorado. Its absence in these counties is
likely due to urban development, which has altered, reduced, or
eliminated riparian habitat (Compton and Hugie 1993; Ryon 1996).
    The third petitioner referred to statements made by unidentified
parties about lack of historical information and about additional
animals being found. We have addressed the issue of insufficient
information in previous paragraphs. We address the issue of additional
surveys and documentation of additional populations in response to
additional statements by the third petitioner below.
    Based on information that (1) the Service has identified numerous
known or potential population areas, and (2) there are large numbers of
unsurveyed sites, the third petitioner concludes that the Preble's is
abundant and has never been threatened.
    The Service did identify areas of known or potential Preble's
populations to assist local governments and other entities in planning
activities (63 FR 66777, December 3, 1998). The sites identified as
``potential'' Preble's population areas had not been surveyed; the
presence of Preble's in these locations was considered possible, but
had not been verified. This list was a preliminary estimate of
potential habitat; some of these potential sites have since been found
not to have suitable habitat and/or not to support Preble's
populations. The potential habitats since found to support Preble's
continue to be subject to the threats listed in the 1998 listing rule.
    The third petitioner asserts that the numbers of known and
potential Preble's habitat indicate its abundance. The list of known or
potential populations identifies fragments of the original Preble's
habitat. The number of fragments may appear high but represent only a
small portion of the original whole. The number of separate sites
reflects the amount of fragmentation that has occurred within historic
habitat and is an indication of the previous and continuing threats to
Preble's habitat described in the 1998 listing rule.
    Additional surveys have been undertaken since the 1998 listing rule
in some locations throughout the subspecies' range where habitat was
believed suitable and where the species was presumed to occur but had
not been documented. Some of these surveys verified Preble's presence
at the survey locations; others did not. While new populations have
been documented and additional animals have been found, the threat
analysis in the 1998 listing rule identified significant threats to the
subspecies and its habitat throughout most of its range in both known
and potentially occupied areas. The newly documented populations remain
subject to the threats analyzed in the 1998 listing rule.
    The third petitioner stated that there is no rational definition of
habitat. Typical habitat for the Preble's comprises well-developed
plains riparian vegetation with adjacent undisturbed grassland
communities and a nearby water source. Well-developed plains riparian
vegetation typically includes a dense combination of grasses, forbs,
and shrubs; a taller shrub and tree

[[Page 70526]]

canopy may be present (Bakeman 1997). When present, the shrub canopy is
often Salix spp. (willow), although shrub species including
Symphoricarpus spp. (snowberry), Prunus virginiana (chokecherry),
Crataegus spp. (hawthorn), Quercus gambelli (Gambel's oak), Alnus
incana (alder), Betula fontinalis (river birch), Rhus trilobata
(skunkbrush), Prunus americana (wild plum), Amorpha fruticosa (lead
plant), Cornus sericea (dogwood), and others also may occur (Bakeman
1997; Shenk and Eussen 1998).
    Additional research on the species' habitat has supported and
refined the definition of habitat used in the 1998 listing rule. This
recent information indicates that, although Preble's have rarely been
trapped in uplands adjacent to riparian areas (Dharman 2001), detailed
studies of the Preble's movement patterns using radio-telemetry found
Preble's feeding and resting in adjacent uplands and traveling
considerable distances along streams, as far as 1.6 km (1.0 mi) in one
evening (Shenk and Sivert 1999a; Shenk and Sivert 1999b; Ryon 1999;
Schorr 2001). These studies suggest that the Preble's uses uplands at
least as far out as 100 m (330 ft) beyond the 100-year floodplain (Ryon
1999; Tanya Shenk, Colorado Division of Wildlife, in litt. 2002).
    The third petitioner also raised several issues specifically
dealing with stated increased costs or private property takings or
life, health, and safety issues, including disease carried by deer
mice. The Code of Federal Regulations (50 CFR 424.11(b)) states that
the Service must make determinations based on the basis of the best
available scientific and commercial information regarding a species'
status, without reference to possible economic or other impacts of such

New Information Available in the Service's Files

    In addition to considering information provided by the petitioners,
if any, the Service also must consider the information readily
available at the time of this finding. Additional information on the
Preble's has become available since the species was listed in 1998 and
since the petitions were received. As cited earlier, numerous surveys
have been undertaken throughout the species' range in suitable habitat
areas where the species was presumed to occur but had not been
documented. Some of these surveys provided verification of Preble's
presence at the survey locations; others did not. The survey results
indicate that the species may persist at or may have been extirpated
from individual survey locations. Research has been conducted, such as
radio-telemetry studies on habitat use and movements by Preble's that
has added to current knowledge about the species' biology. There is new
information verifying differences in morphological characteristics
between Zapus hudsonius preblei and related taxa (Connor and Shenk, in
    Information is available on the presence of and possible increases
in threats to Preble's and its habitat throughout a large portion of
the species' range, as evidenced by--(1) section 7 consultations
conducted to address adverse effects to the Preble's from Federal
actions and (2) applications by private parties for permits to take
Preble's. The Service is in the process of preparing a recovery plan
for the Preble's and is involved in section 7 consultations on Federal
activities as well as assisting with the development of Habitat
Conservation Plans addressing many private activities. Through these
efforts, we are continually reviewing and considering all newly
available information regarding the species' abundance and the threats
it faces.


    The Service has reviewed the petitions, the material submitted with
the petitions and subsequent to the petitions, and additional
information in the Service's files. On the basis of the best scientific
and commercial data available, the Service finds that the petitions and
information in the Service's files do not present substantial
information that delisting the Preble's meadow jumping mouse in
Colorado and Wyoming may be warranted.

References Cited

    A complete list of all references cited in this finding is
available, upon request, from the Lakewood, Colorado Fish and Wildlife
Office (see ADDRESSES section).


    The authority for this action is section 4 of the Endangered
Species Act of 1973 (16 U.S.C. 1531 et seq.).

    Dated: December 11, 2003.
Steve Williams,
Director, Fish and Wildlife Service.
[FR Doc. 03-31255 Filed 12-17-03; 8:45 am]